It has happened to many of us: You are in your home and suddenly hear a telltale thud at your window—the sound of a bird who mistakenly flew into it. In some cases, the bird might flutter off or be “stunned” and then recover. But in many cases, it means death. Another way that you might encounter an unfortunate bird is when a cat killed one and proudly delivered the bird to your doorstep. While window strikes and cat predation might seem like minor occurrences, the numbers can add up to billions of bird deaths annually—just in the United States.
These and other factors were recently examined in a study published last October in SCIENCE magazine. The authors analyzed the population change of 529 bird species in the continental U.S. and Canada from 1970 to 2017. They attributed the decline to habitat loss, agricultural intensification, coastal disturbance, and direct anthropogenic (human-influenced) mortality, all worsened by climate change. “Given that birds are one of the best monitored animal groups, birds may also represent the tip of the iceberg, indicating similar or greater losses in other taxonomic groups,” wrote the authors. They concluded by encouraging the use of conservation and legislation to curb the decline, as these measures have helped certain birds in the past.
As a citizen, wildlife enthusiast, birder, climate activist, conservationist, or all of the above, it can feel daunting to tackle such seemingly insurmountable problems. When we look at the human-influenced factors, however, there are some effective ways in which we can change our own habits and encourage others to as well.
The first and most important way we can help birds is to keep our cats indoors. A 2015 published study examined the anthropogenic, or human-related, causes of bird loss. The authors discovered that, by far, the number one threat to birds in the U.S. is cats, both domestic and feral, who can kill up to two billion birds in the U.S. each year. [The (far) second reason is birds striking windows, discussed below.]
If you currently allow your feline companions to roam outdoors, it might be hard to consider changing your mind when your cat seems to enjoy it so much. But when you consider the effects of predation on birds, not to mention the many hazards your cat might be exposed to, it becomes almost a no-brainer. According to the American Veterinary Medical Association, cats who go outdoors generally have a shorter life span that strictly indoor cats. Outdoor cats can themselves become prey or foes of wild animals, who can kill or injure them. They are also exposed to infectious, parasitic, and zoonotic diseases, could be hit by vehicles, stolen, or assumed to be stray. If you feel your cat must be outdoors, consider placing them in a “catio” (screened-in porch) or other area where they can be safe and birds can be safe from them.
Finally, none of us ever wants to witness the death of a bird who flew into a window. Nearly 600,000 birds die each year in the U.S. after crashing into low and high rise building and residences, according to a 2015 study. The authors noted that “skyscrapers and other large buildings kill the most birds on a per building basis, but individual residences cumulatively kill the most birds.”
Fortunately, there are many products home owners and architects can use to help make windows less confusing both in daytime and nighttime – including clear film coverings, pretty bird decals, and specially patterned glass. See this article from The Cornell Lab of Ornithology for more information on how to prevent window strikes what products or designs they recommend.
– Written by Crystal Miller-Spiegel, Advocacy Committee Member of Bucks Audubon